Method of making a needled composite sheet



N 1969 R. E; CHARLTON, JR., ETAL 3,476,626

METHOD OF MAKING A NEEDLED COMPOSITE SHEET Original Filed Jan. 12, 1962BY Pu s? 7/5, WWI/W54.

Azm/Q FM United States Patent 3,476,626 METHOD OF MAKING A NEEDLEDCOMPOSITE SHEET Richard E. Charlton, Jr., and Rupert A. McDaniel,Fairfax, Ala., assignors to West Point-Pepperell, Inc., a corporation ofGeorgia Continuation of application Ser. No. 165,829, Jan. 12, 1962.This application May 29, 1968, Ser. No. 733,747 Int. Cl. 1332]) 31/20US. Cl. 156-148 2 Claims ABSTRACT OF THE DISCLOSURE A method of formingcomposite products such as auto headliners is disclosed, which comprisesthe steps of contacting a rigid thermoplastic sheet with a non-wovenfibrous web. heating and softening the sheet, and needle punching theweb into said softened sheet, said heating and softening being continueduntil the needle punching is completed. The composite product is readilymoldable with heat and pressure, and suitable for formation into autoheadliners, side panels and the like.

Reference to related application The present application is acontinuation of copending United States application Ser. No. 165,829,filed Jan. 12, 1962, now abandoned.

A principal object of the invention is to provide plastic panels havingtextile simulating surfaces. A further object is to provide moldablepanels of novel decorative nature; the invention encompasses a widerange of decorative and utilitarian variations. A related object is toprovide a simple needle punch method for attachment of non-woven fibrouswebs to rigid thermoplastic sheets, the method being readilycontrollable to produce uniform product in substantially continuousmanner. Still another object is to provide novel apparatus for producingthe composite product of the invention, utilizing as a major elementthereof conventional needle loom equipment. Further objects will be inpart evident and in part pointed out hereinafter.

The invention will be clearly understood from the following descriptionand the accompanying drawings, in which:

FIGURE 1 is a diagrammatic view illustrating an exemplary apparatus andprocedure in accordance with the invention, and

FIGURE 2 is a sectional view, on enlarged scale, of the resultantcomposite product.

Referring to the drawing, FIGURE 1 illustrates a conventional needleloom indicated generally as 10, including the usual needle board 12,needles 14, stripper plate 16 and bed plate 18. 20 represents anextended guide plate mounted adjacent the loom bed plate 18, and leadingthereto, that is on the infeed side thereof. As shown, the uppersurfaces of the bed plate 18 and guide plate 20 are substantiallycoplanar.

Below the bed plate 18 is mounted an electrical resistance heating coil22, controlled by a thermostat 24, and a separate electrical resistanceheating coil 26 is mounted below the guide plate 20, and controlled bythermostat 28. The resistance coils are mounted close to the associatedplates, and desirably adjoin the entire plate area, the coil layoutbeing adapted to evenly heat the plates.

Adjacent the outer end of the guide plate 20 is shown a stack 38 ofplastic sheets 32. Above the guide plate 20 is mounted a supply roll 34of non-woven fabric 36. The fabric 36 extends from supply roll 34 to theguide roll 38, mounted just above the guide plate 20, and therebelow asshown in the drawing. On the outfeed side of the needle 3,476,626Patented Nov. 4, 1969 loom 10 may be provided a coacting pair of driverolls 40, adapted to engage the product leaving the needle loom 10 anddraw the material through the' loom.

The sheets 32, in accordance with the present inventron, may be of anythermoplastic material having a softening point not detrimental to thefibrous web to be applied thereto. Numerous synthetic organicthermoplastic materials may be utilized, including but not limited topolyvinyl chloride, polyvinylidene chloride, polystyrene,polyacrylonitrile, acrylonitrile butadiene styrene, polypropylene, highdensity polyethylene and butadiene styrene. The thermoplastic sheets 32,in accordance with the present invention, are of such thickness as to besubstantially rigid, relatively stiif and self-supporting, and may rangein thickness, for example, from 10 mils or less to 40 mils or more. Theplastic sheets while exhibiting substantial rigidity are yet flexible,although not in the sense of film flexibility, in that the sheets maynot be bent at sharp angles without breaking or permanent deformation.It follows that the thermoplastic sheet material may be supplied inlarge diameter roll form, as well as in individual sheets.

The non-woven fabric 36 may be of any desired type or weight. Thefibrous web may be composed of natural or synthetic fibers, or mixturesthereof, and may be colored, lustered or otherwise decorated as may bedesired. The fibrous web may be lightly bonded, or may be an unbondedweb. In the latter case, a card web or a plurality of crosslaid cardwebs may be utilized and supplied in conventional manner, as on aconveyor belt. The Web may be heavily bonded, if desired, but not to theextent that individual fibers may not be readily displaced therefrom andreoriented. As will be evident, the visual character of the product isdetermined primarily by the fibrous web; an unbonded web will result ina fuzzy or apparently napped surface, a compact relatively heavilybonded web will result in a felt-like surface, and so forth.

As shown in FIGURE 1, plastic sheets 32 may be fed onto the guide plate20 one after another, either manually or by conventional automatic feedmechanism. The plast1c sheets slide along the guide plate until theypass under the guide roll 38, at which point the non-woven fabric 36 isbrought into contact with the upper surface thereof. If deslred, theguide roll 38 may be positively driven, to advance the non-woven fabricand plastic sheets at desired feed rate. The plastic sheet and non-wovenfabric assembly then proceeds over the guide plate 20 to the needle loom10, and is conveniently drawn therethrough by the positively drivendrive rolls 40, although other conventional feed means may be employedas well. If guide rool 38 is driven, its speed will be coordinated withthe speed of rolls 40.

The guide plate 20 is heated by coil 26 to a temperature suitable toheat the plastic sheet material to softening temperature by the time theassembly reaches the needle loom. The exact temperature of the guideplate must necessarily be varied in accordance with the character of thethermoplastic material, its thickness, the feed rate thereof and othervariables. The proper temperature in any case, however, is readilydetermined, and may be maintained by means of the thermostat 28'. Heattransmission to the plastic material by surface contact has been foundto be particularly efficient and readily controllable. The plasticmaterial and/ or guide plate may be heated otherwise than by anelectrical resistance heating coil; for example radiant heaters or opengas flames may be utilized as well. It has been found most efiicient,however, to apply heat to the plastic sheet material through the sideopposite that to which the non-woven fabric is applied], because of theinsulating eifect of the fibrous web.

The plastic sheets with which the invention is concerned cannot beneedled by conventional needle loom equipment under ordinary conditions;due to the thickness of the sheet material, the loom needles would breakor the sheet would be destroyed. It has been found, however, that if thesheet material is properly heat softened, the assembly may readily beneedled. The plastic material cools quickly, however, and it has beenfound necessary to maintain controlled temperature thereof through theneedling operation. For this purpose, the heating coil 22 is providedbelow the bed plate of the loom, whereby the bed plate may be heated toappropriate temperature to maintain the desired softened state of theplastic sheet. The temperature of the loom bed plate 18 is controlled bythermostat 24, and it has been found frequently desirable in practice tomaintain the guide plate 20 and the bed plate 18 at differenttemperatures. In normal practice, it is desirable that the temperatureof the guide plate exceed the temperature of the bed plate, althoughunder some conditions it is preferable to maintain the bed plate at thehigher temperature; in any event, individual temperature control of theguide plate and bed plate facilitates optimum operation.

The needles 14 may be of conventional barb type, and the needle board 12and the throw of the machine are adjusted so that the leading needlebarbs penetrate through the underlying plastic sheet of the assembly.With the plastic material in properly softened condition, the needlespenetrate the plastic sheet without difiiculty, and their barbs engagefibers of the fibrous web and carry some of them into and through theplastic sheet. The resultant composite product is illustrated in FIGURE2, wherein it is indicated that each needle penetration leaves a fiberbundle 42 disposed substantially normal to the product plane, the fiberbundles extending through the non-woven fabric 36 and through the sheetperforations 44, and some distance beyond. It has been found that someof the fibers are pressed by the needles into the walls of theperforations 44, and are firmly locked in place by the plastic materialwhen it cools, whereby the fibrous web is firmly associated with theplastic sheet.

If desired, after completion of the product, a binder solution such asstarch or an elastomeric dispersion may be applied to the plastic sideof the product, in order to more firmly lock the fibers extendingtherethrough. The additional binder coating may be applied at any timeafter the needling operation, in any convenient manner. For example, thebinder may be applied by brushing or spraying. In most cases, however,the fibrous web is firmly aflixed to the plastic sheet by the needlingoperation, and a subsequent bonding step is not necessary.

As previously indicated, the appearance of the fabric side of thecomposite product is determined primarily by the character of thefibrous web or non-woven fabric utilized. This appearance may be alteredslightly by the needling operation, and in such case, of course, theappearance is affected by the extent of needling. The plastic sheet oncooling after the needling operation returns to substantially itsoriginal state of stiffness and rigidity. Since the sheet is perforatedin the course of needling, however, its flexibility is slightlyincreased thereby, and excessive needling may weaken the plastic sheet,and in extreme cases detract from its rigidity and formability.Depending somewhat on the size of the needles employed, the needlingwill usually be within the range of from about 100 to about 1,000punches per square inch, the median part of this range being normallymost desirable. By reason of its rigidity with limited flexibility, theproduct is well suited for use as snap-in panels, either as produced orafter subsequent heat shaping,

The following is a specific example of the invention. Rigidpolypropylene sheets, approximately 20 mils thick and weighing 13.5ounces per square yard, were fed to and across the guide plate 20, and alightly bonded crosslaid web of nylon fibers weighing approximately 6ounces per square yard was applied to the upper surface thereof by meansof guide roll 38. The polypropylene sheets in passage across the guideplate 20 were heated to approximately 300 F., and the temperature of thebed plate 18 was adjusted to maintain the temperature of thepolypropylene material at the same value at the outfeed end of theneedle loom. The feed and operation of the needle loom were adjusted toeifect approximately 400 punches per square inch, and the needle throwadjusted to attain /8 inch penetration through the plastic sheet. Theresultant composite product was substantially rigid and moldable,although exhibiting some flexibility and snap. The fabric side had theappearance of soft woven goods, the needling operation leaving apleasing striated appearance. The fabric web was securely attached tothe plastic sheet backing, and could be detached therefrom only withdifficulty.

We claim:

1. Method of making a composite product comprising the steps ofcontacting a rigid sheet of organic thermoplastic material with anon-woven fibrous web, heating and softening said sheet, and needlepunching said web into said softened sheet to produce about -1000punches per square inch, said heating and softening the sheet beingcontinued until said needle punching is completed.

2. Method of making a composite product comprising the steps ofcontacting one surface of a rigid sheet of organic thermoplasticmaterial with a non-woven fibrous web, said rigid sheet having athickness of about l040 mils, applying heat to the other surface of saidsheet and softening said sheet, needle punching said web into saidsoftened sheet to produce between about 1001000 punches per square inch,said heating and softening the sheet being continued until said needlepunching is completed and permitting the product to cool.

References Cited UNITED STATES PATENTS 1,371,804 3/1921 Nowell l6l642,429,486 10/1947 Reinhardt 161-81 2,639,250 5/1953 Reinhardt l61--662,959,509 11/1960 Marshall 156-448 3,010,180 11/1961 Hoffman l6l154 X3,075,867 1/1963 Cochran 15672 3,205,342 9/1965 Smith et al. 156148 X3,245,854 4/1966 Et-chison et al. l56-148 FOREIGN PATENTS 610,39010/1948 Great Britain.

OTHER REFERENCES Fibers, Plastics, and Rubbers, Roff; published 1956 byButterworths Scientific Publications, London; pp. 360, 361, 362 reliedon.

Modern Plastics, vol. 32, No. 5, January 1955, Porous Plastics Film andSheet, pp. 102 and 103 relied on.

ROBERT F. BURNETT, Primary Examiner RAYMOND O. LINKER, JR., AssistantExaminer U.S. Cl. X.R.

